1. Field of the Invention
The present invention relates to a binding device for holding objects to be bound, such as documents, in a file or a binder. In particular, the invention relates to a binding device for files and binders which is suitable for use as a binding device for so-called A-Z files and which holds objects to be bound such as documents using rings that are opened and closed by a mechanism including a lever.
2. Description of the Related Art
Lever arch files called A-Z files are widely known as files configured such that objects to be bound, such as documents, are held in the files by passing rings through respective binding holes provided near an edge of the objects.
Generally, a lever arch file includes a base and two rings which are firmly attached to the base and extend upwardly and which are inserted into respective holes provided in objects to be bound, such as documents. Each of the rings includes an arch portion and a pole-like portion for holding documents when the file is closed. Furthermore, a mechanism for holding the pole-like portion and the arch portion at a closed position is provided. At the closed position, each of the rings forms a closed loop for holding objects to be bound, and therefore the uppermost page in the bound objects is allowed to slide along the rings, whereby the page therebelow can be read. The above-mentioned mechanism is operated by a lever to allow the above-mentioned two portions to be separated away from each other, whereby objects to be bound can be added through the rings and removed from the rings. Moreover, the two portions of each of the rings can be joined again at the closed position by operating the lever.
A conventional lever arch file is disclosed in Published Japanese Translation of PCT International Application No. 2004-505806 (Patent Document 1).
In conventional lever arch files, each of two rings to be inserted into binding holes in objects to be bound, such as paper sheets, includes an arch portion and a pole-like portion for holding the objects to be bound when the files are closed. Such conventional lever arch files are configured such that when objects to be bound such as paper sheets are bound, the objects to be bound are bound in the pole-like portions by passing binding holes of the paper sheets and the like over the ends of the respective pole-like portions. However, since each arch portion has a shape such that the end thereof points downward even when each of the rings is opened, it is very inconvenient to pass the binding holes of a large number of objects to be bound such as paper sheets toward the arch portion side.
Moreover, the opening-closing mechanism including the lever for opening-closing the arch portions is provided in the center of a base to which the two rings are attached and is configured such that each of the rings can be opened and closed by rotationally moving the lever in a direction orthogonal to the opening-closing direction of each of the rings.
However, in this configuration, when the arch portion of each of the rings is opened, the arch portion touches the lever since it is not sufficiently opened.
Moreover, in lever arch files, a binding device is provided not on the spine of the cover but on the side B since when bound paper sheets are present in pole-like portions, the cover on the side B cannot be closed. Thus, the width of the cover of the files is large, and there is an inconvenience that the storage space for the files is large.